Doc update: Issue with ubuntu 18.04, systemd-resolve dns and minikube

[marcosdiez]

I am basically documenting the solution for #3511 properly.

It stole my whole morning and I don't want anybody else to loose so much time.

If and only if I have time, I might write a proper patch for minikube in the weekend.

For now, this will do.

Above all, thank you @andrewjjenkins

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[minikube-bot]

Can one of the admins verify this patch?

[tstromberg]

Thanks for adding this! My apologies for the time spent :(

We should also see about getting this doc cited when the error occurs, by adding it here:

minikube/pkg/minikube/problem/err_map.go

Line 134 in f74751c

}